low fuel oil temperature effects on boiler operation

7/27/2019 Low Fuel Oil Temperature Effects on Boiler Operation

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Effect of Low Fuel Oil Temperature on Boiler Operation

written by: Dr V T Sathyanathan edited by: Lamar Stonecypher updated: 10/20/2010

Low fuel temperature can lead to a large amount of unburned fuel accumulation in the furnace. This can result in a very high probability for furnace explosion and air

pre-heater fires. Maintaining correct fuel oil temperature ensures good combus tion of fuel and boiler efficiency.

Fuel Oil Temperature and Boiler Operation

Fuel oil is one of the foss il fuesl us ed in boilers to generate steam. The hydrocarbons in fuel oil need heating for reducing the viscosity to a favorable level for

handling and firing. Depending upon the com position of the oil, the effect on performance of boiler can be judged. All oils should have a viscosity of 80 Redwood No 1

at the burner inlet to result in an effective combus tion. The temperature required can be determined by doing a s imple viscosity test in a laboratory. It is a good

practice to check the temperature required to get 80 Redwood No 1 viscosity for each consignment of fuel oil received.

The fuel oil is heated in a fuel oil heater using a condensing type heater. The heated oil is then transported though pipe line to the boiler front and distributed to each

burner through a set of control, trip, and isolation valves. These pipe lines are generally insulated and heat traced using electrical heating or s team heating. The

temperature of the fuel oil at the outlet of the heater is maintained in such a way to take care of the loss of heat in the piping and system so that the viscosity at the gun

tip or gun inlet will be 80 Redwood No 1 and below.

When the fuel oil temperature goes down the operator will have to understand the specific causes, how the plant will respond, what he has to take as an imm ediate

action and how the local operator must respond.

Specific causes

Insufficient steam flow to fuel oil heater

Temperature controller of the heater system faulty

Excessive condensate in the fuel oil heater lowering heat transfer

Faulty steam trap not evacuating the condensate as required

Fuel oil heater can be dirty thus reducing heat transfer

Too high recirculation of fuel oil from heater outlet to the tank

Higher firing rate than design

Plant response

The drop in temperature of fuel oil increases the viscosity leading to poor combus tion

Black smoke from chimney due to unburned carbon s oot carryover

Oil particles carryover to air pre-heater and threat of air pre-heater fire

Immediate operator action

Check the pressure and temperature of steam at the inlet of fuel oil heater

Restore the steam parameter if required

Open steam trap by-pass valve to check for excessive condensate

Remove excessive condensate from the heater

Reduce the oil recirculation if requiredReduce firing rate if needed


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low fuel oil temperature effects on boiler operation

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